Although fatty acids and alcohols in plant polyesters can be useful indicators of organic matter provenance in soils and sediments, interpretation is limited by uncertainty in: (i) the distribution of lipids among plant species and their organs (e.g. leaves and roots) and (ii) the extent to which plant lipid composition is recorded in soils and sediments. In this study, we compare lipids in leaves, roots and soils from 11 temperate tree species. Base hydrolysis was used to release ester-bound lipids and solvent extraction was then used to recover both hydrolysable and " free" lipids. Leaf and root lipid composition varied substantially among the tree species and we highlight differences among evergreen conifers, deciduous broadleaved angiosperms and a deciduous conifer (Larix decidua). Some of the variation appears to be linked to the morphology and lifespan of leaves and roots. Soils preserved much of the variation in the leaf and root lipid composition of the overlying tree species. Yet, the concentration of some lipids in soil diverged from their concentration in tree leaves and roots, reflecting an undocumented input from understory plants and other plant organs (e.g. seeds) or variation in the extent of lipid preservation in soil. Finally, by comparing leaf and root lipid composition, our results help constrain the attribution of lipids to each of these plant organs. This allowed us to evaluate the utility of leaf-derived lipids as plant type biomarkers and to document a substantial contribution of root-derived lipids to soil beneath all 11 tree species.
Bibliographical noteFunding Information:
We thank D. Eissenstat, A. Diefendorf, C. Müller and T. Filley for helpful discussion. D. Eissenstat and P. Reich are acknowledged for administrative support. We are also grateful to B. Bulaj for help in the field and R. Zytkowiak and L. Eccles for assistance in the laboratory. K Quénéa and two anonymous reviewers provided useful comments on the manuscript. K.E.M. and K.H.F. acknowledge support from the U.S. National Science Foundation (NSF), including DEB-0816935 and OISE-0754731. J.O. was also supported by NSF DEB-0128958 and by PBZ-KBN 087/P04/2003 from the State Committee for Scientific Research (Poland). K.E.M. received additional support from a U.S. Department of Energy Graduate Research Environmental Fellowship.